struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->pre_handler) {
+ if (kp->pre_handler && !kprobe_gone(kp)) {
set_kprobe_instance(kp);
if (kp->pre_handler(kp, regs))
return 1;
struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->post_handler) {
+ if (kp->post_handler && !kprobe_gone(kp)) {
set_kprobe_instance(kp);
kp->post_handler(kp, regs, flags);
reset_kprobe_instance();
ap->addr = p->addr;
ap->pre_handler = aggr_pre_handler;
ap->fault_handler = aggr_fault_handler;
- if (p->post_handler)
+ /* We don't care the kprobe which has gone. */
+ if (p->post_handler && !kprobe_gone(p))
ap->post_handler = aggr_post_handler;
- if (p->break_handler)
+ if (p->break_handler && !kprobe_gone(p))
ap->break_handler = aggr_break_handler;
INIT_LIST_HEAD(&ap->list);
int ret = 0;
struct kprobe *ap;
+ if (kprobe_gone(old_p)) {
+ /*
+ * Attempting to insert new probe at the same location that
+ * had a probe in the module vaddr area which already
+ * freed. So, the instruction slot has already been
+ * released. We need a new slot for the new probe.
+ */
+ ret = arch_prepare_kprobe(old_p);
+ if (ret)
+ return ret;
+ }
if (old_p->pre_handler == aggr_pre_handler) {
copy_kprobe(old_p, p);
ret = add_new_kprobe(old_p, p);
+ ap = old_p;
} else {
ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
- if (!ap)
+ if (!ap) {
+ if (kprobe_gone(old_p))
+ arch_remove_kprobe(old_p);
return -ENOMEM;
+ }
add_aggr_kprobe(ap, old_p);
copy_kprobe(ap, p);
ret = add_new_kprobe(ap, p);
}
+ if (kprobe_gone(old_p)) {
+ /*
+ * If the old_p has gone, its breakpoint has been disarmed.
+ * We have to arm it again after preparing real kprobes.
+ */
+ ap->flags &= ~KPROBE_FLAG_GONE;
+ if (kprobe_enabled)
+ arch_arm_kprobe(ap);
+ }
return ret;
}
return -EINVAL;
}
- p->mod_refcounted = 0;
-
+ p->flags = 0;
/*
* Check if are we probing a module.
*/
struct module *calling_mod;
calling_mod = __module_text_address(called_from);
/*
- * We must allow modules to probe themself and in this case
- * avoid incrementing the module refcount, so as to allow
- * unloading of self probing modules.
+ * We must hold a refcount of the probed module while updating
+ * its code to prohibit unexpected unloading.
*/
if (calling_mod != probed_mod) {
if (unlikely(!try_module_get(probed_mod))) {
preempt_enable();
return -EINVAL;
}
- p->mod_refcounted = 1;
} else
probed_mod = NULL;
}
out:
mutex_unlock(&kprobe_mutex);
- if (ret && probed_mod)
+ if (probed_mod)
module_put(probed_mod);
+
return ret;
}
list_is_singular(&old_p->list))) {
/*
* Only probe on the hash list. Disarm only if kprobes are
- * enabled - otherwise, the breakpoint would already have
- * been removed. We save on flushing icache.
+ * enabled and not gone - otherwise, the breakpoint would
+ * already have been removed. We save on flushing icache.
*/
- if (kprobe_enabled)
+ if (kprobe_enabled && !kprobe_gone(old_p))
arch_disarm_kprobe(p);
hlist_del_rcu(&old_p->hlist);
} else {
- if (p->break_handler)
+ if (p->break_handler && !kprobe_gone(p))
old_p->break_handler = NULL;
- if (p->post_handler) {
+ if (p->post_handler && !kprobe_gone(p)) {
list_for_each_entry_rcu(list_p, &old_p->list, list) {
if ((list_p != p) && (list_p->post_handler))
goto noclean;
static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
{
- struct module *mod;
struct kprobe *old_p;
- if (p->mod_refcounted) {
- /*
- * Since we've already incremented refcount,
- * we don't need to disable preemption.
- */
- mod = module_text_address((unsigned long)p->addr);
- if (mod)
- module_put(mod);
- }
-
- if (list_empty(&p->list) || list_is_singular(&p->list)) {
- if (!list_empty(&p->list)) {
- /* "p" is the last child of an aggr_kprobe */
- old_p = list_entry(p->list.next, struct kprobe, list);
- list_del(&p->list);
- kfree(old_p);
- }
+ if (list_empty(&p->list))
arch_remove_kprobe(p);
+ else if (list_is_singular(&p->list)) {
+ /* "p" is the last child of an aggr_kprobe */
+ old_p = list_entry(p->list.next, struct kprobe, list);
+ list_del(&p->list);
+ arch_remove_kprobe(old_p);
+ kfree(old_p);
}
}
#endif /* CONFIG_KRETPROBES */
+/* Set the kprobe gone and remove its instruction buffer. */
+static void __kprobes kill_kprobe(struct kprobe *p)
+{
+ struct kprobe *kp;
+ p->flags |= KPROBE_FLAG_GONE;
+ if (p->pre_handler == aggr_pre_handler) {
+ /*
+ * If this is an aggr_kprobe, we have to list all the
+ * chained probes and mark them GONE.
+ */
+ list_for_each_entry_rcu(kp, &p->list, list)
+ kp->flags |= KPROBE_FLAG_GONE;
+ p->post_handler = NULL;
+ p->break_handler = NULL;
+ }
+ /*
+ * Here, we can remove insn_slot safely, because no thread calls
+ * the original probed function (which will be freed soon) any more.
+ */
+ arch_remove_kprobe(p);
+}
+
+/* Module notifier call back, checking kprobes on the module */
+static int __kprobes kprobes_module_callback(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct kprobe *p;
+ unsigned int i;
+
+ if (val != MODULE_STATE_GOING)
+ return NOTIFY_DONE;
+
+ /*
+ * module .text section will be freed. We need to
+ * disable kprobes which have been inserted in the section.
+ */
+ mutex_lock(&kprobe_mutex);
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, node, head, hlist)
+ if (within_module_core((unsigned long)p->addr, mod)) {
+ /*
+ * The vaddr this probe is installed will soon
+ * be vfreed buy not synced to disk. Hence,
+ * disarming the breakpoint isn't needed.
+ */
+ kill_kprobe(p);
+ }
+ }
+ mutex_unlock(&kprobe_mutex);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kprobe_module_nb = {
+ .notifier_call = kprobes_module_callback,
+ .priority = 0
+};
+
static int __init init_kprobes(void)
{
int i, err = 0;
err = arch_init_kprobes();
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
+ if (!err)
+ err = register_module_notifier(&kprobe_module_nb);
+
kprobes_initialized = (err == 0);
if (!err)
else
kprobe_type = "k";
if (sym)
- seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type,
- sym, offset, (modname ? modname : " "));
+ seq_printf(pi, "%p %s %s+0x%x %s %s\n", p->addr, kprobe_type,
+ sym, offset, (modname ? modname : " "),
+ (kprobe_gone(p) ? "[GONE]" : ""));
else
- seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr);
+ seq_printf(pi, "%p %s %p %s\n", p->addr, kprobe_type, p->addr,
+ (kprobe_gone(p) ? "[GONE]" : ""));
}
static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
- arch_arm_kprobe(p);
+ if (!kprobe_gone(p))
+ arch_arm_kprobe(p);
}
kprobe_enabled = true;
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
- if (!arch_trampoline_kprobe(p))
+ if (!arch_trampoline_kprobe(p) && !kprobe_gone(p))
arch_disarm_kprobe(p);
}
}
projects / linux-2.6-omap-h63xx.git / commitdiff